Composite used for light control of privacy

ABSTRACT

A composite including a polymeric film having a first generally planar major surface and an opposite second major surface defined by a multiplicity of elongate parallel contiguous ridge portions. The ridge portions each have a generally triangular cross section and elongate obscured and transmitting second major surface portions intersecting at the apex of the ridge with the obscured second major surface portion being on the side of the ridge generally facing a first end of the sheet and the transmitting second major surface portions being on the side of the ridge portions adjacent a second end of the sheet. The film can provide visual transmission between its first major surface and the transmitting second major surface portions while coatings along the obscured second major surface portions prevent viewing of visual images through the film; whereas the composite can also provide light transmission between the first major surface and the transmitting second major surface portions, while the coatings along the obscured second major surface portions restrict light transmission.

This is a continuation of application Ser. No. 08/263,450 filed Jun. 21,1994 now abandoned.

TECHNICAL FIELD

This invention relates to composites used for light control (i.e.,composites that will only pass light along predetermined paths), orcomposites used for privacy (i.e., composites for covering objects suchas computer screens or the like that will restrict viewing of thoseobjects to persons looking at those objects from predeterminedorientations relative to a major surface of the composite).

BACKGROUND OF THE INVENTION

Composites are known that will only pass light along predetermined pathsthrough the composite and/or can be used to cover objects such ascomputer screens or the like to thereby restrict viewing of thoseobjects to persons looking at those objects from predeterminedorientations relative to a major surface of the composite. One knowncomposite of this type consists of elongate parallel alternate layers ofopaque and transparent materials extending between opposite major sidesurfaces and opposite ends of the composite so that images can only beseen through the composite when it is viewed at generally a right angleto the major surfaces of the composite, and light can only pass throughthe composite at that same angle. Such composites have been made byphotolithography, microreplication, or skiving. While such compositesare useful for some purposes, they can be expensive to make, theyrestrict viewing images or direct light in patterns that are notentirely suitable for some applications, and some absorb light so thatthey darken the image of the object.

DISCLOSURE OF THE INVENTION

The present invention provides a composite that can be adapted for useas a light control film to direct light in novel patterns that areuseful for many applications; and can be adapted for use as a privacycomposite that can not only be used to cover objects such as computerscreens, but also can advantageously be used to cover documents tothereby restrict viewing of those objects to persons looking at thoseobjects from different, more desirable predetermined orientationsrelative to a major surface of the privacy composite than can the knowncomposites described above. The light control and/or privacy compositeaccording to the present invention is less expensive to make than theprior art light control composite described above, is flexible and lightin weight, and can fairly easily be adapted to provide different viewingor light transmission orientations relative to a major surface of theprivacy composite to accommodate different applications for which it maybe used.

The composite according to the present invention comprises a polymericfilm having a first generally planar major surface defined by asheet-like main portion having a generally rectangular cross section;and a multiplicity of elongate parallel contiguous ridge portions joinedto and projecting less than 2 millimeters (and preferably less than 1millimeter) from the side of the main portion opposite the first majorsurface. The ridge portions define a second major surface for the filmand each has a generally triangular cross section and elongate obscuredand transmitting second major surface portions intersecting at the apexof the ridge with the obscured second major surface portion being on theside of the ridge adjacent or generally facing the first end of thesheet and the transmitting second major surface portion being on theside of the ridge adjacent the second end of the sheet. The anglebetween the transmitting second major surface portion of each ridge andan imaginary plane parallel to the first major surface and passingthrough the apexes of the ridge portions is in the range of 25 to 60degrees and is preferably in the range of 35 to 40 degrees; whereas theincluded angle between the transmitting and obscured second majorsurface portions at the apex of each ridge portion is in the range of 50to 130 degrees and is preferably about 90 degrees. In the privacycomposite, the film provides visual transmission between its first majorsurface and the transmitting second major surface portions and theprivacy composite includes means along the obscured second major surfaceportions for preventing viewing of visual images through the film;whereas in the light control composite the film provides lighttransmission between the first major surface and the transmitting secondmajor surface portions, and the composite includes means along theobscured second major surface portions for restricting lighttransmission through the obscured second major surface portions.

Such a composite can direct light rays incident on its first majorsurface through the composite, and/or can afford viewing of objectsalong its first major surface only along a light receiving or viewingarea (see the darkened area of FIG. 3). That light receiving or viewingarea is in the shape of about one half of a hemisphere projecting fromthe second major surface and centered on those rays, is adjacent thesecond end of the sheet, and is closer in shape to half of a hemisphereat its apex than around its base. The result of a viewing area of thatshape is that when the privacy composite is used to cover objects suchas documents, the viewing area allows a person at the second end of theprivacy composite to quite easily see the document, while persons alongthe first end or at the sides of the privacy composite are restrictedfrom seeing it.

The means along the obscured second major surface portions forpreventing viewing of visual images through the film or for restrictinglight transmission through the obscured second major surface portionscan comprise one or more thin layers of metal over the obscured secondmajor surface portions. In the privacy composite, the metal used in suchlayers and its thickness is selected to (1) prevent a document along thesecond side of the film from being read through the obscured secondmajor surface portions, (2) to restrict glare from light reflected backthrough the first major surface of the film by the metal layer, (3) toprovide a pleasing appearance for the film when it is viewed from otherthan the predetermined orientations relative to its first major surface,and, (4) can also be selected to reflect light incident along the secondmajor surface of the film to thereby help illuminate an object such as adocument adjacent to that second major surface.

Suitable layers of metal or other materials along the obscured secondmajor surface portions should have thicknesses in the range of 10 to1500 nanometers, and preferably have thicknesses in the range of 40 to100 nanometers. Such layers can, for example, be of aluminum, aluminumoxide, copper, gold or chromium used singly or in combinations. One suchcombination is thin (e.g., 100 nanometers thick) layers of aluminum overthe obscured second major surface portions, and thin (e.g., 10nanometers thick) layers of aluminum oxide over the layer of aluminum.Such layers of aluminum cause the sheet to have a reflective metallicappearance to persons looking at the first major surface of the filmfrom orientations other than the predetermined orientations at whichobjects along the second major surface can be viewed. Another suchcombination which is expensive, but surprisingly effective, is thin(e.g., 10 nanometers thick) layers of chromium over the obscured secondmajor surface portions, and thin (e.g., 100 nanometers thick) layers ofgold over the layers of chromium. Such layers of chromium cause thesheet to have a pleasing non-glaring dark metallic appearance to personslooking at the first major surface of the film from orientations otherthan the predetermined orientations at which objects along the secondmajor surface can be viewed, while the layers of gold are quitereflective to help illuminate objects adjacent the second major surfaceof the film. Relatively inexpensive yet effective single layers are thin(e.g., 70 nanometers thick) layers of chromium over the obscured secondmajor surface portions, which layers of chromium cause the sheet to havea pleasing non-glaring dark metallic appearance to persons looking atthe first major surface of the film from orientations other than thepredetermined orientations at which objects along the second majorsurface can be viewed.

Alternatively, in the privacy composite the means along the obscuredsecond major surface portions for preventing viewing of visual imagesthrough the film can be provided by making the obscured second majorsurface portions sufficiently rough that they are incapable oftransmitting visual images (as can be done with the point of a diamondtool); and in either composite that means may be a pigmented or dyedcoating.

Protection for the ridges and coatings on the obscured second majorsurface portions can be provided, which is particularly desirable whenthe privacy composite is portable to prevent the ridge portions and/orcoatings from becoming scratched or otherwise damaged. Such protectionfor the ridges and coatings can be in the form of a protectivetransparent polymeric layer attached over the ridges, or such protectionfor the coatings can be provided by a suitable coating of uniformthickness along the second major surface of the film.

The privacy composite can be incorporated as one wall of a file folderor similar structure adapted to receive documents between adjacentwalls, or can be adapted in size and by being three hole punched for useas a cover page in a three ring binder.

The privacy composite can advantageously be used in combination with asheet-like light source to read a document therebetween; and also, thecomposite can be used in combination with a sheet-like light source toprovide a directional lighting strip.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be further described with reference to theaccompanying drawing wherein like reference numerals refer to like partsin the several views, and wherein:

FIG. 1 is a perspective view of a composite according to the presentinvention having ridge portions thereof much enlarged to show detail;

FIG. 2 is a enlarged fragmentary inverted edge view of the composite ofFIG. 1;

FIG. 3 is a schematic view of a light receiving or viewing area (shownin dark grey) of the composite of FIG. 1;

FIG. 4 is a tracing of light rays from a point light source passingthrough the composite of FIG. 1;

FIG. 5 is a plotting of the intercepts of rays from the light source ofFIG. 4 on a plane parallel to and spaced from the composite of FIG. 1;

FIG. 6 is an enlarged fragmentary view illustrating a possiblemodification for obscured second major surface portions on the compositeof FIG. 1;

FIG. 7 illustrates certain modifications of the composite of FIG. 1;

FIG. 8 illustrates the composite of FIG. 1 modified to be incorporatedin a folder;

FIG. 9 illustrates a further modification of the composite of FIG. 1;

FIG. 10 illustrates the composite of FIG. 1 being used in combinationwith a sheet-like light source to read a document therebetween; and

FIG. 11 illustrates the composite of FIG. 11 being used in combinationwith a sheet-like light source to provide a lighting strip.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2 of the drawing, there are shown muchenlarged views of a composite according to the present inventiongenerally designated by the reference numeral 10.

Generally the composite 10 comprises a polymeric film 11 having agenerally planar first major surface 12, an opposite second majorsurface 13, and first and second opposite ends 8 and 9. The composite 10can be adapted and used to direct light from objects (e.g., a lightedinstrument panel) adjacent the second major surface 13 of the film 11only to persons looking at the objects from predetermined orientationsrelative to the first major surface 12 of the film 11, or can be adaptedand used to restrict viewing of objects adjacent the second majorsurface 13 of the film 11 to persons looking at the objects frompredetermined orientations relative to the first major surface 12 of thefilm 11. The film 11 comprises a main portion 14 having a generallyrectangular cross section and defining the first major surface 12; and amultiplicity of elongate parallel contiguous ridge portions 15 joined toand projecting less than 2 millimeters (and preferably less than 1millimeter) from a side of the main portion 14 opposite the first majorsurface 12. The ridge portions 15 define the second major surface 13.Each of the ridge portions 15 has a generally triangular cross sectionwith an apex opposite the main portion 14. Also, each of the ridgeportions 15 has an elongate obscured second major surface portion 17 anda transmitting second major surface portion 18, which portions 17 and 18intersect at the apex of the ridge portion 15. The obscured second majorsurface portions 17 are on the side of the ridge portions 15 adjacent orgenerally facing the first end 8 of the sheet 11 and the transmittingsecond major surface portions 18 are on the side of the ridge portionsadjacent or generally facing the second end 9 of the sheet 11. The angle"a" between the transmitting second major surface portion 18 and animaginary plane parallel to the first major surface 12 and passingthrough the apexes of the ridge portions 15 (see FIG. 2) is in the rangeof 25 to 60 degrees, and the included angle "b" between the transmittingand obscured second major surface portions 18 and 17 at the apexes ofthe ridge portions 15 (see FIG. 2) is in the range of 50 to 130 degrees.When the composite 10 is used or adapted for use to control light, thefilm 11 provides light transmission between its first major surface 12and its transmitting second major surface portions 18, and the composite10 includes means along the obscured second major surface portions 17for restricting light transmission through the obscured second majorsurface portions 17. When the composite 10 is used for or adapted foruse as a privacy composite, the film 11 provides visual transmissionbetween its first major surface 12 and its transmitting second majorsurface portions 18, and the privacy composite 10 includes means alongthe obscured second major surface portions 17 for restricting viewing ofvisual images through the obscured second major surface portions 17.

The composite 10 will direct light rays incident on its first majorsurface 12 through, or afford viewing of objects along, its first majorsurface 12 only along a light receiving or viewing area 20 shown as adarkened area in FIG. 3. That light receiving or viewing area 20 is inthe shape of about one half of a hemisphere projecting from and having acenter along the first major surface 12 and centered on those rays. Thelight receiving or viewing area 20 is adjacent the second end 9 of thesheet 11 and comes closer to the boundary of half of a hemisphere at itsapex 21 than it does around its base 22. When the composite 10 is usedto cover objects such as documents with its second major surface 13,that viewing area 20 provides the advantage that a person at the secondend 9 of the composite 10 can quite easily see the document, whilepersons along the first end 8 or the sides of the privacy composite 10are restricted from seeing it.

FIG. 4 illustrates the path of rays 22 directed to the privacy composite10 from a point light source 23 along the second major surface 13 of thefilm 11 when the angle "a" is 35 degrees, the angle "b" is 90 degrees,and the material of the film 11 has an index of refraction of 1.6. FIG.5 is a computer generated diagram illustrating by + signs where themajority of the light rays 22 from the light source 23 would fall on aplane 24 (see FIG. 4) parallel to the first major surface 12 of the film11 and spaced from the film 11 by a distance about 100 times the spacingbetween two adjacent ridge portions 15. The + signs form a dark area 26where the majority of the rays strike the plane 24. By changing theangles "a" and "b" and the material of the film 11, the area in whichthe majority of the light rays 22 will strike the plane 24 can be movedon the plane 24, and thereby a desired light directing or viewingpattern can be selected for the film 11.

As described above, the means along the obscured second major surfaceportions 17 for restricting light transmission through the obscuredsecond major surface portions 17 or for restricting viewing of visualimages through the obscured second major surface portions can comprisecoatings or thin layers 28 of opaque material (e.g., aluminum, aluminumoxide, copper, gold, chromium, pigmented or dyed coatings or multiplelayers of such materials) over the obscured second major surfaceportions 17. Alternatively, as is illustrated in the enlarged fragmentof a modified one of the obscured second major surface portions 17aillustrated in FIG. 6, that means for restricting light transmissionthrough the obscured second major surface portions can be provided bythe film 11a being sufficiently rough along the obscured second majorsurface portions 17a (which rough major surface portions 17a can beformed with a diamond tool) to restrict viewing images through theobscured second major surface portions 17a.

Preferably the first major surface 12 has a textured or matte finishwhich restricts glare along the first major surface of the composite 10.Examples of suitable materials for the film 11 which include ridgeportions of the type described above are the acrylic or polycarbonatematerials sold under the trade designations "Scotch Brand OpticalLighting Film" (called "SOLF" hereinafter) or "Brightness EnhancementFilm" (called "BEF" hereinafter) by Minnesota Mining and ManufacturingCompany, St. Paul, Minn. Alternatively, the film 11 can be formed from alayer of polycarbonate, polymethylmethacrylate, polyalkyl (meth)acrylicacid esters, polycarbonate, polystyrene, acrylated epoxies, acrylatedurethanes, acrylated polyesters, cellulosic esters, or multifunctional(meth)acrylic acid esters.

When the composite 10 is adapted to be used with its major surfaces 12and 13 in a generally horizontal orientation, preferably the angle "a"between each transmitting second major surface portion 18 and animaginary plane parallel to the first major surface 12 and passingthrough the apexes of the ridge portions 15 is in the range of about 35to 45 degrees, and the included angle "b" between the transmitting andobscured second major surface portions 18 and 17 is about 90 degrees.Applications for such horizontal use include use as a privacy composite10 over documents being read on the top surface of a desk or overoriginals or copies on a copy machine (i.e., over the feeding orreceiving stations of the copy machine).

When the composite 10 is adapted to be used with its major surfaces in agenerally vertical orientation, preferably the angle "a" between eachtransmitting second major surface portion 18 and an imaginary planeparallel to the first major surface 12 and passing through the apexes ofthe ridge portions 15 is in the range of about 30 to 40 degrees, and theincluded angle "b" between the transmitting and obscured second majorsurface portions 18 and 17 is about 90 degrees. Applications for suchvertical use include use as a privacy composite 10 over the screen on acomputer or over a document in a vertically disposed document holderthat may, for example, be associated with a computer or typewriter; oruse as a light control composite over the face of a lighted instrumentdial, or over the lighted instrument cluster of an automobile in whichcase the light control composite 10 can allow the driver to read theinstruments while preventing light from those instruments from beingdirected toward the windshield.

Protection for the very small ridge portions 15 and the coatings 28 ofopaque material along the obscured second major surface portions 17should be provided when the composite 10 is portable or otherwise isused in a way that the second major surface 13 of the film 11 could beabraded (e.g., scratched against objects along the top of a desk). As isillustrated in FIG. 7, such protection can be provided in a privacycomposite 10b including a film 11 of the type described above by aprotective transparent polymeric layer 30 having a periphery 32corresponding in shape and size to the periphery of the film 11b. Theprotective transparent polymeric layer 30 overlays the second majorsurface 13 of the film 11 and the peripheries of the film 11 and theprotective transparent polymeric layer 30 are bonded together as by heatsealing or by a suitable adhesive. Alternatively, such protection forthose coatings could be provided by a protective transparent outercoating (not illustrated) having a generally uniform thickness overthose coatings and the uncoated portions of the second major surface 13.As is illustrated, optionally the privacy composite 10b can be adaptedfor use as a cover page in a three ring binder by being of theappropriate size and by being punched to form three holes 31.

As is illustrated in FIG. 8 the privacy composite 10b described abovecan be incorporated in or form one side of a folder 32 which also has asecond side 34 that is pivotably attached to the privacy composite alongone edge 35 and can be positioned along the protective transparent layer30 to receive a document to be read therebetween. That document couldthen be read through the first major surface 12 of the film 11. Whilenot illustrated, the privacy composite could also be incorporated as thefront wall of an envelope having a second side sealed along all but oneside to the privacy composite 10b and adapted to receive documentsbetween that second side and the protective transparent layer 30 of theprivacy composite 10b.

FIG. 9 illustrates an embodiment 10c of the privacy composite which iselongate in a direction parallel to its ridge portions 17c. Thecomposite 10c has film 11c having the structure of the film 11 describedabove, and includes a protective transparent polymeric layer 30c havinga width and length generally corresponding to the width and length ofthe film 11c. The protective transparent polymeric layer 30c overlaysthe second major surface 13c of the film 11c and the film 11c and theprotective transparent polymeric layer 30c are bonded together by edgeportions of the polymeric layer 30c being adhered or otherwise attachedalong the edges of the film 11c. The transparent polymeric layer 30c iscoated on its side opposite the film 11c with a layer 36 of eitherrepositionable, removable or permanent pressure sensitive adhesive. Sucha strip privacy composite 10c could be supplied in strips or on ahelically wound roll from which lengths could be removed, and could beadhered over portions of a document to restrict certain writteninformation thereon from other than the reader of that document.

As is illustrated in FIGS. 10 and 11, the privacy composite 10 can beused in combination with a sheet-like light source 40 of the type soldby Durel Corporation, Tempe, Ariz., under the trade designation "Durel3" electroluminescent lamp. When an appropriate A.C. voltage source 42is connected to that light source 40, it will emit a relatively brightlight. As is illustrated in FIG. 10, that sheet-like light source 40 canbe used under a document 44 over which the privacy composite 10 ispositioned to illuminate that document 44 for a reader (as may bedesirable in the dark or under low light conditions). As illustrated inFIG. 11, that sheet-like light source 40 may be used directly along thesecond major surface 13 of the composite 10 to thereby provide adirectional light source which may be useful in the dark or under lowlight conditions in many places such as along an edge of a computerkeyboard to illuminate its keys, or along an edge of a folder tofacilitate reading documents in the folder.

The film 11 can be made by extrusion casting/embossing as is describedin U.S. Pat. No. 4,097,634; by compression molding as is described inU.S. Pat. Nos. 4,244,683 and 4,601,861; or by casting and curing (thepreferred method) as is described in U.S. Pat. Nos. 3,689,346,5,175,030, and 5,183,597. The contents of the patents listed above inthis paragraph are hereby incorporated herein by reference. A thin metalor metal oxide coating can be deposited over both surfaces of the ridgesusing known vapor coating techniques. Subsequently, that coating can beablated from the transmitting second major surface portions by themethod described in European Patent Specification EP 0583997-A1, thecontent whereof is incorporated herein by reference.

EXAMPLES

Example 1: SOLF having "a" angles of 45 degrees and "b" angles of 90degrees and having ridge portions spaced at 360 micrometers was firstprimed with vapor coated chromium and then coated with 75 nanometers ofgold. The film was ablated at a 45 degree angle with respect to itsfirst major surface with a 248 nanometer Lambda Physik LPX315i excimerlaser. Depending on the viewing angle, the composite had either a brightgold or transparent appearance from its second major surface. Theappearance of the composite from its first major surface varied from adark purple color to transparent. The composite had less than 5% lighttransmission in the high extinction viewing range. Ray tracing indicatedthat this transmission was actually reflection off the metal coatedsurface of the obscured second major surface portions. The ridgeportions of the composite were discernible but did not appearobjectionable.

Example 2: film having "a" angles of 45 degrees and "b" angles of 90degrees and having ridge portions spaced at 50 micrometers that waspattern replicated from BEF in 50/50 hexanedioldiacrylate/Photomer 6010with 1 percent Darocur 4265 on 20 mil thick polycarbonate film wasmetallized with 75 nanometers of chromium. This film was demetallized asdescribed above. The angular performance of the resulting composite wassimilar to Example 1. The ridge portions of the composite were notvisible at any normal viewing distance.

Example 3: A film having "a" angles of 30 degrees and "b" angles of 90degrees was generated as described in Example 2. Ablation was done at 45degrees, which may have caused some damage to the metal on the risers.The film was very bright but did not cut off until about -45 degrees.

Example 4: The film of example 1 was coated with a semitransparentcoating of 15 nanometers of Aluminum which was reacted with 8 SCCM ofoxygen during the deposition to increase the UV absorptivity of thefilm. The film was ablated as described in Example 1. The film wasplaced on paper with the grooves down. The viewing angle was identicalto the examples with "a" angles of 45 degrees, however the brightnesswas higher. Surprisingly, the ghost images were not significant. Asecond, non-overlapping image was visible at high vertical angles.

Example 5. The material produced as described in Example 1 was placed ona cathode ray tube with the ridge portions adjacent the tube. The imagewas not visible at a normal angle due to the 45 degree "a" angles. Theimage was clear and free of ghosts over a viewing range from 75 to 85degrees.

The present invention has now been described with reference to severalembodiments and modifications thereof. It will be apparent to thoseskilled in the art that many changes can be made in the embodimentsdescribed without departing from the scope of the present invention.Thus the scope of the present invention should not be limited to thestructures described in this application, but only by structuresdescribed by the language of the claims and the equivalents of thosestructures.

We claim:
 1. A composite comprising:a flexible polymeric film having agenerally planar first major surface, first and second opposite ends,and a multiplicity of elongate parallel contiguous ridge portionsdefining a second major surface opposite said first major surface, eachof said ridge portions having an apex opposite said first major surface,and each having generally planar elongate obscured and transmittingsecond major surface portions intersecting at said apex and definingelongate v-shaped grooves having depths of less than 2 millimetersbetween the apexes of adjacent ridges with the obscured second majorsurface portions being on the sides of the ridge portions generallyfacing the first end of the sheet and the transmitting second majorsurface portions being on the sides of the ridge portions generallyfacing the second end of the sheet, the angle between said transmittingsecond major surface portions and an imaginary plane parallel to thefirst major surface and passing through the apexes of the ridge portionsbeing in the range of 25 to 60 degrees, and the included angle betweensaid transmitting and obscured second major surface portions at theapexes of said ridge portions being in the range of about 50 to 130degrees, said film providing light transmission through and between saidfirst major surface and said transmitting second major surface portions,and said composite including means along said obscured second majorsurface portions for restricting light transmission through saidobscured second major surface portions so that said composite willdirect light through the composite from objects adjacent the secondmajor surface of the film only to persons looking at the objects frompredetermined orientations relative to the first major surface of thefilm.
 2. A composite according to claim 1 wherein said means along saidobscured second major surface portions for restricting lighttransmission through said obscured second major surface portionscomprises thin layers of aluminum over said obscured second majorsurface portions, and layers of aluminum oxide over said layers ofaluminum.
 3. A composite according to claim 1 wherein means along saidobscured second major surface portions for restricting lighttransmission through said obscured second major surface portionscomprises thin layers of chromium over said obscured second majorsurface portions, and layers of gold over said layers of chromium, saidlayers of chromium causing said privacy composite to have a darkmetallic appearance to persons looking at the first major surface of thefilm from orientations other than said predetermined orientations, andsaid layers of gold being highly reflective of light away from saidsecond major surface to help illuminate an object adjacent said secondmajor surface.
 4. A composite according to claim 1 wherein means alongsaid obscured second major surface portions for restricting lighttransmission through the said obscured second major surface portionscomprises first thin layers of aluminum oxide over said obscured secondmajor surface portions, layers of aluminum over said first layers ofaluminum oxide, and second layers of aluminum oxide over the sides ofsaid layers of aluminum opposite said first layers of aluminum oxide,said aluminum oxide having the formula ALOx where x is in the range of 0to 1.5.
 5. A composite according to claim 1 wherein means along saidobscured second major surface portions for restricting lighttransmission through the said obscured second major surface portionscomprises thin layers of materials selected from the group consisting ofaluminum, aluminum oxide, copper, gold and chromium.
 6. A compositeaccording to claim 1 wherein said means along said obscured second majorsurface portions for restricting light transmission through the saidobscured second major surface portions comprises pigmented or dyedcoatings over said obscured second major surface portions.
 7. Acomposite according to claim 1 wherein said means along said obscuredsecond major surface portions for restricting light transmission throughthe said obscured second major surface portions comprises said filmbeing sufficiently rough along said obscured second major surfaceportions to restrict light transmission through said obscured secondmajor surface portions.
 8. A composite according to claim 1 wherein saidv-shaped grooves have depths of less than 1 millimeter.
 9. A compositeaccording to claim 1 wherein the angle between said transmitting secondmajor surface portions and an imaginary plane parallel to the firstmajor surface and passing through the apexes of the ridge portions is inthe range of 30 to 45 degrees, and the included angle between saidtransmitting and obscured second major surface portions is in the rangeof 70 to 110 degrees.
 10. A composite according to claim 1 adapted to beused with said first major surface in a generally vertical orientationwherein the angle between said transmitting second major surfaceportions and a plane parallel to the first major surface and passingthrough the apexes of the ridge portions is in the range of about 30 to40 degrees, and the included angle between said transmitting andobscured second major surface portions is about 90 degrees.
 11. Acomposite according to claim 1 adapted to be used with said first majorsurface in a generally horizontal orientation wherein the angle betweensaid transmitting second major surface portions and an imaginary planeparallel to the first major surface and passing through the apexes ofthe ridge portions is in the range of about 35 to 45 degrees, and theincluded angle between said transmitting and obscured second majorsurface portions is about 90 degrees.
 12. A composite according to claim1 wherein said first major surface has a textured or matte finish.
 13. Acomposite according to claim 1 further including a protectivetransparent polymeric layer having a periphery corresponding in shapeand size to the periphery of said film, said protective transparentpolymeric layer overlaying said second major surface of said film andthe peripheries of said film and said protective transparent polymericlayer being bonded together.
 14. A composite according to claim 1 incombination with a sheet-like light source positioned along the secondmajor surface of the film, said combination being adapted to provide adirectional light source.
 15. A privacy composite comprising:a flexiblepolymeric film having a generally planar first major surface, first andsecond opposite ends, and a multiplicity of elongate parallel contiguousridge portions defining a second major surface opposite said first majorsurface, each of said ridge portions having an apex opposite said firstmajor surface, and each having generally planar elongate obscured andtransmitting second major surface portions intersecting at said apex anddefining elongate v-shaped grooves having depths of less than 2millimeters between the apexes of adjacent ridges with the obscuredsecond major surface portions being on the sides of the ridge portionsgenerally facing the first end of the sheet and the transmitting secondmajor surface portion being on the side of the ridge generally facingthe second end of the sheet, the angle between said transmitting secondmajor surface portions and an imaginary plane parallel to the firstmajor surface and passing through the apexes of the ridge portions beingin the range of 25 to 60 degrees, and the included angle between saidtransmitting and obscured second major surface portions at said apexbeing in the range of 50 to 130 degrees, said film providing visualtransmission between said first major surface and said transmittingsecond major surface portions, and said privacy composite includingmeans along said obscured second major surface portions for restrictingviewing of visual images through said obscured second major surfaceportion so that said privacy composite will direct light through theprivacy composite from objects adjacent the second major surface of thefilm only to persons looking at the objects from predeterminedorientations relative to the first major surface of the film.
 16. Aprivacy composite according to claim 15 wherein said means along saidobscured second major surface portions for restricting viewing of visualimages through the film comprises thin layers of aluminum over saidobscured second major surface portions, and layers of aluminum oxideover said layers of aluminum.
 17. A privacy composite according to claim15 wherein means along said obscured second major surface portions forrestricting viewing of visual images through the film comprises thinlayers of chromium over said obscured second major surface portions, andlayers of gold over said layers of chromium, said layers of chromiumcausing said sheet to have a dark metallic appearance to persons lookingat the first major surface of the film from orientations other than saidpredetermined orientations, and said layers of gold being highlyreflective of light away from said second major surface to helpilluminate an object adjacent said second major surface.
 18. A privacycomposite according to claim 15 wherein means along said obscured secondmajor surface portions for restricting viewing of visual images throughthe film comprises first thin layers of aluminum oxide over saidobscured second major surface portions, layers of aluminum over saidfirst layers of aluminum oxide, and second layers of aluminum oxide overthe sides of said layers of aluminum opposite said first layers ofaluminum oxide, said aluminum oxide having the formula ALOx where x isin the range of 0 to 1.5.
 19. A privacy composite according to claim 15wherein means along said obscured second major surface portions forrestricting viewing of visual images through the film comprises thinlayers of materials selected from the group consisting of aluminum,aluminum oxide, copper, gold and chromium.
 20. A privacy compositeaccording to claim 15 wherein said means along said obscured secondmajor surface portions for restricting viewing of visual images throughthe film comprises layers of pigment over said obscured second majorsurface portions.
 21. A privacy composite according to claim 15 whereinsaid means along said obscured second major surface portions forrestricting viewing of visual images through the film comprises saidobscured second major surface portions being sufficiently rough so as tobe incapable of transmitting visual images.
 22. A privacy compositeaccording to claim 15 wherein said v-shaped grooves have depths of lessthan 1 millimeter.
 23. A privacy composite according to claim 15 whereinthe angle between said transmitting second major surface portions and animaginary plane parallel to the first major surface and passing throughthe apexes of the ridge portions is in the range of 30 to 45 degrees,and the included angle between said transmitting and obscured secondmajor surface portions is in the range of 70 to 110 degrees.
 24. Aprivacy composite according to claim 15 adapted to be used with saidfirst major surface in a generally vertical orientation wherein theangle between said transmitting second major surface portion and animaginary plane parallel to the first major surface and passing throughthe apexes of the ridge portions is in the range of about 30 to 40degrees, and the included angle between said transmitting and obscuredsecond major surface portions is about 90 degrees.
 25. A privacycomposite according to claim 15 adapted to be used with said first majorsurface in a generally horizontal orientation wherein the angle betweensaid transmitting second major surface portions and an imaginary planeparallel to the first major surface and passing through the apexes ofthe ridge portions is in the range of about 35 to 45 degrees, and theincluded angle between said transmitting and obscured second majorsurface portions is about 90 degrees.
 26. A privacy composite accordingto claim 15 wherein said first major surface has a textured or mattefinish.
 27. A privacy composite according to claim 15 further includinga protective transparent polymeric layer having a peripherycorresponding in shape and size to the periphery of said film, saidprotective transparent polymeric layer overlaying said second majorsurface of said film and the peripheries of said film and saidprotective transparent polymeric layer being bonded together.
 28. Aprivacy composite according to claim 27 further including a second layerhaving a periphery corresponding in shape and size to at least a portionof the periphery of said protective transparent polymeric layer, saidsecond layer being bonded to said protective transparent polymeric layeralong a portion of said periphery on the side of said protectivetransparent polymeric layer opposite said film to define a pockettherebetween adapted to receive a sheet along the first major surface ofsaid film.
 29. A privacy composite according to claim 15 furtherincluding a protective coating having a generally uniform thickness oversaid second major surface.
 30. A privacy composite according to claim 15in combination with a sheet-like light source positioned along thesecond major surface of the film, said combination being adapted toreceive a document between said privacy composite and said sheet-likelight source.